Saturday from 4:30 p.m., a terrace at the Thistle by Terminal 5, and a runway full of departures. Wanna Come Plane Spotting takes over the space again for aircraft, aviation chat, and, weather permitting, a proper sunset over the heavies. Bring a camera, layers, and your best "that's a special livery" energy. Free; the hotel lends the terrace, so buy a drink at the bar.